Accurate origin determination of seafood is crucial for consumer trust and safety. This study was performed to develop a machine learning-based single-nucleotide polymorphism (SNP) analysis technique to determine the origin of Acetes species in salted small-shrimp products. Mitochondrial DNA (COI and 16S rRNA) analysis revealed genetic variations among species and origins. Eight candidate SNPs were identified, six of which were developed into markers for genotyping analysis. Using the developed markers, an SNP array was created and SNP data from salted small-shrimp samples were obtained. Machine learning analysis using a supervised learning algorithm achieved 100% accuracy in classifying the origin of Acetes based on SNP data. This method offers a reliable method for regulatory bodies to combat food fraud and ensure product integrity. The approach can be further improved by expanding the data set to encompass a wider range of species and origins. This study highlights the potential of SNP analysis and machine learning for ensuring seafood authenticity and promoting sustainable practices.

Olive flounder (Paralichthys olivaceus) is a vital aquaculture species in East Asia. However, few studies that estimate the genetic parameters of this species have been conducted. We estimated the genetic parameters of growth traits and designed an optimum breeding programme for this species. Heritability, genetic and phenotypic correlations, and breeding values were estimated for growth traits: body weight (BW), total length (TL), and condition factor (CF). A linear mixed animal model using the restricted maximum likelihood (REML) algorithm was applied to the statistical analysis of 9 traits (BW, TL, and CF at 11, 18, and 22 months of age) for a total of 54,159 animals from 7 generations. Increases of 13%, 8%, and 6.5% in BW, TL, and CF at the harvest stage were observed, respectively, after 7 generations of selection. The heritabilities of all growth traits were moderate, ranging from 0.35 to 0.46. The phenotypic and genetic correlations between BW and TL were high and positive in all three stages (0.91 and 0.92, 0.91 and 0.93, and 0.88 and 0.91). The estimated breeding values of BW and TL increased over the generations; however, the estimated breeding value of CF fluctuated. The optimum progeny number within full-sib families for an accuracy of 0.632 is suggested to be between 10 and 25. Findings indicated that a considerable response to selection and single-trait selection based on BW would be effective in olive flounder.

Interferon Regulatory Factor 3 (IRF3) is a member of interferon-regulated transcription factor family and is known to play an important role in the innate immune response against viral infections. In this study, the expression of IRF3 in different tissues, developmental stages, and stocking densities of olive flounder was investigated. The expression of IRF3 was observed to gradually increase in early-stage juvenile fish. The highest expression was observed in later-stage juvenile fish when immune tissues were formed. High IRF3 expression was observed in the muscles and the brain tissues. The expression of IRF3 was observed in fish at different stocking densities after viral hemorrhagic septicemia virus (VHSV) infection. It yielded an interesting expression pattern in the muscles and the brain tissues of fish stocked at low density. These observations can be used as basic data for the study of the expression of immune response-related genes against viruses based on stocking density and immune systems in other fish species.

The caspase10 encodes an initiating caspase that plays an important role in the maintaining the cellular homeostasis by regulating the steps involved in the immune response and cell death. We investigated the expression of caspase10 during the different developmental stages and in olive flounder tissues. Caspase10 increased in the late stage of the formation of immune tissue, and high expression was observed in the gills, kidney, skin, and spleen. The current study analyzed the expressional changes of caspase10 in olive flounder infected with viral hemorrhagic septicemia virus (VHSV). One of the major causes of mass mortality, VHSV infection in olive flounder attributes to significant expression of caspase10 in the gills, spleen, skin, and kidneys. The results indicate a close association of caspase10 expression with the immune response to VHSV infection in olive flounder. The observations could form the basis data for exploration of other fish immune system.

Eel populations are globally threatened by overfishing and illegal trade, making accurate species identification essential for resource conservation and regulatory enforcement. Conventional molecular identification methods are generally applied in the laboratory, with limited rapid on-site application. This study developed a field-deployable assay to identify the Japanese eel (Anguilla japonica), by incorporating multienzyme isothermal rapid amplification (MIRA) technology with a visually readable lateral flow assay (LFA). Species-specific primers targeting a 286 bp region within the mitochondrial genome of A. japonica were designed and labeled with fluorescein amidite and biotin, respectively. The performance of the MIRA-LFA was validated by assessing its specificity against four other major eel species and its analytical sensitivity, i.e., limit of detection (LoD), under optimized temperature and reaction-time conditions. The MIRA-LFA demonstrated 100% specificity, generating a positive signal only for A. japonica, with no cross-reactivity. A clear visual result was obtained within 10 min at the optimal reaction temperature of 39 °C. Under these optimal conditions, the assay showed a high sensitivity, with an LoD of 0.1 ng/μL of genomic DNA. The proposed assay is an effective tool for the rapid, specific, and sensitive identification of A. japonica. The ability to obtain fast, equipment-free visual results makes this assay an ideal point-of-care testing solution to combat seafood fraud and support the sustainable management of this economically important and vulnerable species.